In some medical conditions, such as, Chronic Obstructive Pulmonary Disease (COPD), Asthma, and Cystic Fibrosis (CF), an excessive volume of viscoelastic material, which is called lung mucus, may be built up in the lung of a patient. Excessive lung mucus is known to cause severe problems due to an increased chance of lung infections, declined lung function, reduced effect of inhaled medicine etc.
The removal of excessive lung mucus is therefore highly beneficial to the health status of a patient. Normally patients are instructed to cough in special ways (called directed cough) or breathe in special patterns (called Huffing), but both often do not result in the desired effect.
Currently, an oscillation device to assist a cough is provided for Cystic Fibrosis and Chronic Obstructive Pulmonary Disease patients in order to increase lung mucus clearance. The oscillation can be air oscillation pressure transmitted to a lung through a mouth for causing the airways of a lung to oscillate. The oscillation also can be mechanical oscillation pressure transmitted to a lung through the ribcage and muscles, like for example High Frequency Chest Wall Oscillations (HFCWO).
However, based on the current oscillation device, when oscillation is generated in the airways of a lung, a periodic oscillation airflow is generated, and the direction of the periodic oscillation airflow may be different from the direction of cough (exhalation) airflow during a cough, which may impede the cough.